Opinion polls over the past few months have consistently suggested that in the upcoming general election, no party will achieve a Lok Sabha majority and that India would return to the 30-year pattern in the seven elections between 1989 and 2009.

If that happens, we will see one of those rare occasions when India’s head of state can – and must – exercise power independently.

President Ram Nath Kovind will need to decide whom to call to form a government. Much will depend on the parliamentary arithmetic – on how many seats different parties and alliances have won. If no party or alliance has a huge lead, he will have multiple options available.

As in the past, various constitutional ‘experts’ will rush into print to say that the president ‘must’ do one thing or another. We may hear that he ‘must’ call the leader of the largest single party, or of the largest multi-party alliance, or of the alliance that may provide the greatest long-term stability, even it has fewer MPs than another alliance. The ‘experts’ will cite different precedents or conventions – Indian or foreign – that he ‘must’ follow.

They will all be wrong.

The constitution gives the president complete freedom to do what he pleases. His secretariat has systematically compiled a full list of previous Indian (but not foreign) episodes and decisions by presidents (but not state governors) to provide him with guidance. These records suggest different actions, but he is not bound to adopt any of them.

President Kovind will face a serious dilemma if the Bharatiya Janata Party and the National Democratic Alliance that it heads fall far short of a majority. Even if they win many more seats than any rivals, he may still have a problem.

There are clear signs that the BJP’s remaining allies in the NDA are unhappy about Prime Minister Modi’s radical centralisation of power within the government. His refusal to respond to allies’ concerns has already caused some parties to leave the NDA. Those that are still on board may demand more generous treatment and the award of ministries that offer significant power and – not incidentally – fund-raising opportunities.

Their views are shared by many leaders within the BJP who have found that even apparently prominent cabinet posts do not guarantee influence in a system in which policy making is largely done within the Prime Minister’s Office. This writer has heard bitter complaints from senior BJP figures in Bihar, Karnataka and Delhi about the refusal of Modi and Amit Shah to listen to their ideas during unsuccessful state election campaigns. Many formidable leaders within the BJP would share the desire of other NDA parties for a new prime minister.

That view also appears to have gained ground within the Rashtriya Swayamsevak Sangh. It has made no secret of its preference for government through institutions rather than by individuals. One-man dominance and the glorification of a single leader are not to their liking. There have even been suggestions that they would prefer Nitin Gadkari as prime minister. And if some of Gadkari’s recent statements are anything to go by, he appears to be positioning himself for that possibility.

President Kovind may find himself caught in these cross-currents. One of the only things that he ‘must’ do is summon not a party or an alliance but an individual party leader to attempt to form a government. If he is inclined to turn to a new BJP leader, he will face two difficulties.

First, in India as in most parliamentary systems, the office of prime minister does not fall vacant between or immediately after an election. On the day that the result becomes known, the president will find the incumbent – Narendra Modi – occupying that post. Given Modi’s strong appetite for power, the president can expect robust resistance to any change of leader.

Second, the only way for Modi to be displaced by a different BJP leader will probably be through a vote of its parliamentary party. But it will be logistically challenging to convene that body swiftly enough to overcome the inevitable, robust and swift efforts by Modi and Shah to prevent any change.

President Kovind, and India, may face a testing time once the result is known.

James Manor is a professor in the School of Advanced Study, University of London. He is the author of numerous books including Power, Poverty and Poison: Disaster and Responsein an Indian City (1993) on the 1981 hooch disaster in Bangalore.